Origami inspires development of 3D printed TWISTER robots at Case Western Reserve

Sep 28, 2017 | By David

As 3D printing technology expands the range of possible structures and functions for robotics, soft robotics in particular is starting to get creative with its designs. Origami is one source of inspiration that engineers keep coming back to, and a new 3D printed robotics project based on the ancient Japanese folding art was recently developed by a team of researchers at Ohio’s Case Western Reserve University.

The project was led by Kiju Lee, the Nord Distinguished Assistant Professor of Mechanical and Aerospace Engineering at CWRU, and her lab. Lee's team moved from inital trials using paper robots to the development of a fully 3D printed model that can bend, contract, extend, and twist. This novel robot has been dubbed TWISTER (TWISted TowEr Robot).

The specific jumping-off point for this innovative project was a work by Japanese artist Mihoko Tachibana. The team saw the potential in this structure, which was a tower made of multiple origami segments, to be implemented in the design of a robot that could have a broad range of applications.

Early trials of the work using paper-folded structures saw Lee's team adding three small versions of the towers to one end of a larger tower, and manipulating them to grasp like three opposing fingers. Loads of different sizes, such as eggs or fruit, were applied to see how the structure would fare in supporting them and moving them around. The team found that the finger-like elements were able to absorb the extra force by redistributing it and deforming its shape accordingly.

This deformability is one of the key benefits that soft robotics projects such as TWISTER have over more traditional robots, and in this case it will make the technology applicable in a number of incredibly useful ways. For example, because of its ability to support and manipulate objects in the way that it can, the robot doesn't need any extra sensors to detect forces and adjust itself. The amount of necessary human intervention is therefore drastically reduced.

Another benefit of soft robots is their improved safety. According to Lee, "Among the possibilities for this robot are fragile-object manipulation and direct human-robot interaction, because these robots are soft and safe."

3D printing enabled the production of complex shapes and highly intricate, origami-based structures. Each TWISTER bot is made up of multiple layers of regular polygons: triangles, hexagons, and octagons, forming a tube-like shape of a tower. Cable-based actuation is currently used by Lee to control her creations, but she has also looked into the possibility of using Shape Memory Alloys to make them even more autonomous.

Lee has been in talks with medical professionals, discussing ways to miniaturize the TWISTER robots in order to insert them in the body, for some minimally invasive surgeries. "Laproscopic surgery often requires some rigid pieces, and movement to control them from the outside causes stress on the tissues," Lee said.

These innovative little robots might even end up leaving Earth altogether, if the project progresses further. According to Lee, "To put anything into space, volume and weight are critical, because of the cost of rocket transport.This robot is fully collapsible and, compared to a rigid arm, light and compact."